Задание 12, стр.35

#include <iostream>
#include <cstdlib>
#include <string>
#include <vector>
#include <stdarg.h>
#include <algorithm>

using namespace std;


class CD{


vector<string> compositions;

public:
    string name;
    CD(string name)
    {
    this->name = name;
    }
    ~CD(){compositions.clear();}
    vector<string>::iterator begin()
    {
        return compositions.begin();
    }
     vector<string>::iterator end()
    {
        return compositions.end();
    }
    string pick(int i)
    {
        return compositions[i];
    }
    int getSize(){
        return compositions.size();
    }
    void add(string title)
    {
           compositions.push_back(title);
    }
    void pop(string title){
        compositions.erase(find(compositions.begin(), compositions.end(), title));
    }
    void print(){
        if (compositions.size() > 0)
            cout << name + ": \n" << endl;
        for(int i = 0; i < (int)compositions.size(); i++)
            cout << " -" << compositions[i] << endl;
    }
};
 bool operator < (CD a, CD b)
    {
        int n = a.getSize();
        if (n > b.getSize())
            return false;
        if (n < b.getSize())
            return true;
        for(int i = 0; i < n; ++i)
            {
                if (a.pick(i) == b.pick(i))
                    continue;
                if (a.pick(i) < b.pick(i))
                    return true;
                return false;
            }
    }
    bool operator == (CD a, CD b){
        if (a.getSize() != b.getSize())
            return false;
        sort(a.begin(), a.end());
        sort(b.begin(), b.end());
        int n = a.getSize();
        for(int i = 0; i < n; ++i)
            if (a.pick(i) != b.pick(i))
                return false;
        return true;
    }

class Catalog{
    vector<CD> cd;

public:
    Catalog(){}
    ~Catalog(){cd.clear();}

    void add(CD cd){
        this->cd.push_back(cd);
    }
    void pop(CD cd){
        this->cd.erase(find(this->cd.begin(), this->cd.end(), cd));
    }
    void pop_track(string CD_name, string trackName){
        int n = cd.size();
        for(int i = 0; i < n; ++i)
            if (cd[i].name == CD_name)
                cd[i].pop(trackName);

    }
    void print(){
        int n = cd.size();
        for(int i = 0; i < n; i++)
            {
                cd[i].print();
                cout << endl;
            }
    }
    void print(string CD_name){
        int n = cd.size();
        for(int i = 0; i < n; ++i)
            if (cd[i].name == CD_name)
                cd[i].print();
    }

};


int main()
{
    Catalog myCatalog;
    CD Noize("Noize"), Letov("Letov");
    Noize.add("Sea");
    Noize.add("Work");
    Letov.add("Def");
    myCatalog.add(Noize);
    myCatalog.add(Letov);
    myCatalog.print();
    cout << endl << endl;
    myCatalog.pop_track("Noize", "Sea");
    myCatalog.print();
    cout << endl << endl;
    myCatalog.print("Noize");

}